Touch-sensitive displays (also known as “touch screens” or “touchscreens”) are well known in the art. Touch screens are used in many electronic devices to display graphics and text, and to provide a user interface through which a user may interact with the devices. A touch screen detects and responds to contact on the touch screen. A device may display a GUI comprising one or more soft keys, menus, and other user-interface objects on the touch screen. A user may interact with the device by contacting the touch screen at locations corresponding to the user-interface objects with which he/she wishes to interact.
Touch screens are becoming more popular for use as displays and as user input devices on handheld electronic devices, such as mobile telephones and personal digital assistants (PDAs). FIGS. 1A and 1B illustrate a handheld electronic device 100 with a portrait and a landscape screen orientation, respectively. The handheld device 100 includes a rigid case 102 for housing the components of the handheld electronic device 100 that is configured to be held in a user's hand while the handheld electronic device 100 is in use. The handheld electronic device 100 comprises a touch screen 104 mounted within a front face of the case 102. The electronic device 100 may also comprise one or more control buttons 106 which may or may not be included in the touch screen 104. The touch screen 104 displays a GUI comprising a virtual keyboard 108 comprising one or more soft keys.
Presently in both the portrait screen orientation (as shown in FIG. 1A) and the landscape screen orientation (as shown in FIG. 1B), the virtual keyboard 108 is located in a lower portion of the GUI relative to the orientation of the touch screen 104 (and typically the current orientation of the device 100) so that it may be more easily touched (or actuated) using the thumbs or other fingers of the user while the user is holding the device 100. In some embodiments, the device components may be configured and dimensioned so that the user may hold the handheld electronic device 100 in such a manner to enable two-thumb typing on the virtual keyboard 108 using both hands. One problem associated with requiring typing by both hands is that sometimes the user may only have one hand available to hold and operate the handheld electronic device 100 while the other hand is occupied with other tasks. In such situations, the user may not be able to reach all the soft keys on the virtual keyboard 108 due to the limited length of one's thumb or any other fingers.
In other embodiments, the device components may be configured and dimensioned so that the handheld electronic device 100 can be cradled in the palm of a user's hand and the virtual keyboard 108 may be touched with the thumb of the hand of the user in which the handheld electronic device 100 is being held. One problem associated with using only one hand to both hold the handheld electronic device 100 and touch the virtual keyboard 108 which is located in the lower portion of the GUI is that the user's hand may get easily tired because he/she has to constantly stretch and stroke her thumb, for example, to compose a lengthy email message. In yet other embodiments, as the device dimension increases in order to provide more functionalities and/or larger screen display, it will become more difficult for a user to both hold the device 100 and touch the virtual keyboard 108 when the keyboard 108 is located in the lower portion of the GUI as shown in FIGS. 1A and 1B.
These drawbacks may reduce the ease of use of the virtual keyboard user interface and, as a consequence, the ease of use of the handheld electronic device 100 in general. Accordingly, there is a need for a more user-friendly interface for text and number input using the virtual keyboard.